Bio Exam II Flashcards
osmoregulation
regulation of solute concentrations and the balance of water
osmosis
movement of water from a region of higher concentration to a region of lower concentration
osmolarity
solute concentration of a solution that determines the movement of water across a semi permeable membrane
iso-osmotic
movement of water is equal in both directions
what happens is two solutions differ in osmolarity?
the net flow of water is from the hypo-osmotic to the hyper-osmotic
hypo-osmotic
solution with lower concentration of solute
hyper-osmotic
solution with a higher concentration of solute
the fluid with the highest osmolarity is?
seawater in a tidal pool
osmoregulation and excretion are?
mechanisms that maintain volume and composition of body fluids
organisms categorized as osmoconformers are most likely?
marine species
osmoconformers
consists only of some marine animals, are iso-osmotic with their surroundings and do not regulate their osmolarity
osmoregulators
expend energy to control water uptake and loss in a hyper-osmotic
osmoregulator examples
most vertebrates -
all freshwater fishes
most amphibians
all terrestrial animals
osmoconsumers
all marine invertebrates
elasmobranches (sharks, rays, and hagfish)
osmolarity of osmoregulators is
1/3 rd of seawater
Freshwater animals
constantly take in water by osmosis from their hypo-osmotic environment
they lose salts by diffusion and maintain water balance by excreting large amounts of dilute urine
salts lost by diffusion are replaced in foods and by uptake across the gills
Marine animals
constantly lose water by osmosis from their hyper-osmotic environments
gain salts by diffusion and maintain water balance by not peeing
energy of osmoregulation
osmoregulators must expend energy to maintain osmotic gradients therefore they are actively transporting substances across cell memebranes
land animals
have adaptations to reduce water loss
body coverings of most help to prevent dehydration
nocturnal lifestyle can help with water savings
maintain water balance by eating moist food and producing water metabolically
nitrogenous waste
breakdown of proteins and nucleic acids
some animals convert toxic ammonia to less toxic compounds prior to excretion
catabolism
breakdown of proteins and nucleic acids
ammonia
animals that excrete nitrogenous waste as ammonia need access to lots of water
mostly fish who release it across whole body surface or through gills
urea
mammals, most amphibians, sharks and some bony fishes
liver converts ammonia to less toxic urea
How is urea excreted
circulatory system carries urea to kidneys where it is excreted
process of ammonia conversion to urea is energetically expensive
excretion of urea requires less water than ammonia
